I"ve had a hard time finding the straight answer on this topic especially as it relates to the rear doors. After reading many posts and piecing together information I dove in.

I'm providing detailed information in case it helps anyone else: This is for my 2009 ML 63. I don't know if there is a difference on other MLs. I can only speak to my experience with my car.

Problem: replace original plastic door pins with AMG aluminum versions
Mercedes parts used (as provided by both this forum and AMG website):
AA 000 766 02 28. These are sold individually- not in pairs as you would expect so they can get expensive. I ended up making this mistake when I ordered from a mercedes website ($64 each). Fortunately, I found them for sale on Ebay for $34.00 each later. The First Door took me 30 minutes to do, the rest only about 10 minutes each

Step1: measured original pins in raised and lowered positions

Step2: using a towel and pliers, I carefully unscrewed the original pins normally (counter clockwise). NOTE: due to the very soft plastic, you will badly mar the original pins. You're pretty much committed to this task after this. It took a number of tedious turns until it was loose enough for me to remove with my fingers. All doors were in UNLOCKED position so the stems would be raised and easier to work with. NOTE: ALL door pins including the rear were the same. I did the exact same steps on all four doors and all doors looked the same before, during and after the install

Step3: I applied 2 good drops of medium strength Locktight threadlock to the door pin stem and then 2 good drops inside the new AMG pins and let each dry for about 2 minutes. I made sure I had a towel down when applying to the pins and one handy to wipe up any excess on the doors. its very thin liquid so its easy to run.

Step4: carefully screwed on the new AMG door pins but only to where they were slightly below 7/8" this is just a hair below the originals. I did this instead of making them flush for safety but still threaded enough to be good. If locks fail and you or others need to manually lift them, there is still enough to grab onto. Because the new pins are shorter (but the correct ones), they won't feel tight on the stem when installing but they'll firm up after the Locktight dries. I made sure the AMG logos were nicely aligned on each door

Step5: Leave them alone overnight so they dry (tempting to play with them but don't). The next day I made sure all the pins didnt wiggle and were firm on the doors. Looks good.

replaced tires with Continental DWS 295\40\20. Tread is different from Continental UHP. I was concerned this wouldn't look good but they do. drive is also improved and treadware and wet driving is much better

also did a front tint on my window by an experience front window tinter. Visibility is near clear but UV damage to my dash is nearly removed and the heat in my car significantly reduced. NOTE that front window tinting is not legal in all states. Just do a quick Google search to see if it is in yours. For Texas, this is legal